A conventional method of preserving a microorganism and animal derived material is disclosed, according to which AC or negative DC voltage in the range from 100 V to 5000 V is applied across an electrode to generate an electrostatic field atmosphere, and a microorganism or animal derived material is placed in the electrostatic field atmosphere at −20° C. to −40° C. for preservation. In this way, the microorganism or animal derived material is preserved in the electrostatic field atmosphere with the AC or negative DC voltage in the range from 100 V to 5000 V, preferably from 100 V to 3000 V, so that the microorganism or animal derived material can be preserved without inactivating or deactivating its activity or killing it (see for example JP 2005-112839 A).